The HSE has adopted RNA PCR as the gold standard test for diagnosing Covid-19 cases, which has been deployed as part of the HSE test and trace strategy, consistent with international best practice.
Testing for Covid-19 only provides a point-in-time result. It confers no guarantee that the individual with a 'not detected' result is not incubating the infection or the level of virus is below detectable levels at the time of the test. It is for this reason that testing of close contacts of a confirmed case is carried out on two separate occasions, when they are first identified and again 7 days after their last contact with the person.
Success in detecting Covid-19 is affected by the timing of sampling, the type and quality of the sample and the test used to analyse the sample. However, no single test is 100% sensitive or 100% specific. Extensive validations have been carried out in our laboratories, with national collation of data, to ensure that the tests used show high sensitivity.